DRAW CIRCLE, DRAW DISK (original enhancement)
draws a circle of radius 1 and of center the origin with the line color.
The beam shall be set off.
draws a circle and fill the interior of it with the area color.
The beam shall remain.
These can be transformed. For example,
if you want to draw a circle of radius r, center (x,y), write
DRAW circle WITH SCALE(r)*SHIFT(x,y)
Refer to picture definition
CIRCLE and DISK are not reserved words.
Thus a user can define a picture of its name "CIRCLE" or "DISK".
If the circle crosses a line at infinity as a result of transformation, The DRAW statements above do not draw proper figures.
On such a case, the following picture definition is effective.
1000 EXTERNAL PICTURE circle 1010 OPTION ANGLE DEGREES 1020 FOR t=0 TO 360 1030 PLOT LINES : COS(t),SIN(t); 1040 NEXT t 1050 END PICTURE 2000 EXTERNAL PICTURE disk 2010 OPTION ANGLE DEGREES 2020 OPTION BASE 0 2030 DIM x(359),y(359) 2040 FOR t=0 TO 359 2050 LET x(t)=COS(t) 2060 LET y(t)=SIN(t) 2070 NEXT t 2080 MAT PLOT AREA : x,y 2090 END PICTURE